In this work chemical sensors based on polyaniline and on polyaniline/graphenenanosheets bilayer were prepared by dip coating. Their morphology and volatile organic compounds (VOCs) sensing behavior were compared. In particular, the devices were investigated in presence of VOCs as limonene and ethanol. Furthermore the devices were characterized under relative humidity. Bilayer samples, exposed to limonene, show a higher relative response respect to only polyaniline, encouraging the graphene use in VOCs sensor devices. © Springer International Publishing Switzerland 2015.